The present invention relates to a method and apparatus for maintaining a capillary tube or a small diameter continuous hydraulic conduit in a well bore to inject fluids into or produce fluids from a well; specifically, the method and apparatus for inserting a capillary tube through a well head and production tubing past the wellhead master valves and/or a down hole safety valve and selectively removing the capillary tube if the valve must be closed and reinserting the tube when the valve is re-opened.
In the drilling and completion of oil and gas wells throughout the world, the need to insert small diameter continuous hydraulic conduits or tubes into the well's production tubing has arisen on numerous occasions and for a variety of purposes. Typically, this was accomplished by lowering the continuous hydraulic conduit through the well head, it's master valves, and then down through the production tubing, through any sub-surface safety valves and on down into the well bore from a surface spool system. Substantial cost savings result from the ability to quickly move onto a wellhead site and dispose a small diameter conduit down the well bore without the need of workover rigs or large coiled tubing injector head assemblies. Previously, when the treatment or task was completed, the tubing was withdrawn from the well bore, since it was imprudent to leave a conduit or tube suspended through a safety valve or well head master valve. Very often, it is beneficial to leave the small diameter tubing in the well bore, for example, to chemically treat the well below the safety valve or well head master valves; as, for example, by extending the tube on down the well bore to the production zone. Since these tubes extend past both the well head valves and one or more downhole safety valves, if the well pressures must be controlled, the small diameter continuous hydraulic conduit must be capable of being withdrawn from the well bore before the wellhead valve or the downhole safety valve is closed.
The ability to selectively or automatically move the small diameter continuous hydraulic conduit into and out of a well valve without completely removing the conduit from the well has heretofore not been accomplished.